The Knights won 42-10 against Doncaster, but Luke Stenchion (suspended) is unavailable this week.
Sam Scott (knee) missed training on Tuesday, but Thornton is hopeful he will be fit to take part on Sunday.
Thornton said: “We were excellent last week compared to how we’ve been previously, and now we’ve got to kick on.
“We’ve got another really important game against Keighley, a team near us on the table, and we’re looking to back up last week’s effort.”
March said: “Our game management was good in the first half, and then we closed them out well in the last 15 minutes.
“That will give us some confidence, but so too does having our best 17 on the park for the first time this year.
“We’ll go into this game against York unchanged, and I probably haven’t said that all season.
“York had a strong win last week and they’ve beaten Featherstone at home as well. It’ll be battle, but hopefully one we can overcome.”